Patent Document 1 discloses one of valve devices that have a fuel tank-use cutoff valve and means for detecting whether a fuel tank is filled up with fuel. The device includes an evaporator opening at the upper portion of a housing accommodating a float valve, and a fuel opening at the lowermost portion. When the fuel surface reaches the fuel opening by the fuel being supplied, the float valve rises and closes the evaporator opening. This allows the fuel level inside the filler pipe to rise, and the sensor of a fuel supply gun to detect that the fuel tank is filled up with the fuel, so as to stop the fuel supply. A through hole is provided at the upper portion of the housing of the device. Once the oil supply is stopped, the balance is achieved between the pressure inside the housing and the pressure inside the tank by ventilation through this through hole. This allows the fuel level in the housing to lower, and the float valve lowers. In this state, since ventilation through the through hole and the evaporator opening is established, the pressure inside the tank lowers and the fuel level inside the filler pipe also lowers, whereby the state where additional fuel supply is possible is created. However, the device disclosed in Patent Document 1 is just simply provided with the through hole at the housing; therefore, the float valve is prone to lower immediately after it is detected that the fuel tank is filled up with the fuel. When the fuel level inside the filler pipe lowers immediately after the fuel tank being filled up is detected, the automatic stop of the fuel supply gun is released, which enables immediate additional fuel supply, and invites excessive fuel supply.